Global correlation and local information flows in controllable non-Markovian open quantum dynamics

Xin-Yu Chen,Xiang-Yu Kong,Ming-Jie Tao,Na-Na Zhang,Fu-Guo Deng,Wan-Ting He,Gui-Lu Long,Qing Ai

doi:10.1038/s41534-022-00537-z

Abstract

In a fully-controllable experiment platform for studying non-Markovian open quantum dynamics, we show that the non-Markovianity could be investigated from the global and local aspects. By mixing random unitary dynamics, we demonstrate non-Markovian and Markovian open quantum dynamics. From the global point of view, by tuning the base frequency we demonstrate the transition from the Markovianity to the non-Markovianity as measured by the quantum mutual information (QMI). In a Markovian open quantum process, the QMI decays monotonically, while it may rise temporarily in a non-Markovian process. However, under some circumstances, it is not sufficient to globally investigate the non-Markovianity of the open quantum dynamics. As an essential supplement, we further utilize the quantum Fisher information (QFI) flow to locally characterize the non-Markovianity in different channels. We demonstrate that the QMI in combination with the QFI flow are capable of measuring the non-Markovianity for a multi-channel open quantum dynamics.

Highlights

Quantum coherence and entanglement lie at the heart of important resources for quantum metrology and quantum information processing[1,2]
A specific model in which the noise Hamiltonian commutes with the system Hamiltonian is utilized in order to obtain the analytical results
In practice the system-bath interaction generally do not commutate with the system Hamiltonian

Summary

Introduction

Quantum coherence and entanglement lie at the heart of important resources for quantum metrology and quantum information processing[1,2]. Due to interaction with the environment, any quantum system inevitably suffers from decoherence and quantum entanglement disappears at a finite time[3,4]. Environment does not always play a harmful role and some interesting phenomena may rise in open quantum dynamics with structured baths. In a spin bath, multidecoherence processes may be slower than single-decoherence processes when applied with appropriate pulse sequences[5,6]. In radical-pair mechanism for avian compass, the local magnetic environments compete against the homogeneous geomagnetic field to affect the yield of chemical reaction and effectively play the role of measuring instrument for the weak geomagnetic field[7,8]. The environment can assist efficient energy transfer toward the reaction center in natural photosynthesis[9,10]

Methods

Results

Conclusion